Implement fsverity functionality

Implement calls to the fsverity kernel module, allowing containerd to
enable fsverity on blob data in the content store. This causes fsverity
to veirfy the integrity of blob data when the blob is read.

Signed-off-by: James Jenkins <James.Jenkins@ibm.com>

plugins/content/local/writer.go

@@ -27,6 +27,7 @@ import (
 	"time"
 
 	"github.com/containerd/containerd/v2/core/content"
+	"github.com/containerd/containerd/v2/pkg/fsverity"
 	"github.com/containerd/errdefs"
 	"github.com/containerd/log"
 	"github.com/opencontainers/go-digest"
@@ -137,6 +138,14 @@ func (w *writer) Commit(ctx context.Context, size int64, expected digest.Digest,
 		return err
 	}
 
+	// Enable content blob integrity verification if supported
+
+	if w.s.integritySupported {
+		if err := fsverity.Enable(target); err != nil {
+			log.G(ctx).Warnf("failed to enable integrity for blob %v: %s", target, err.Error())
+		}
+	}
+
 	// Ingest has now been made available in the content store, attempt to complete
 	// setting metadata but errors should only be logged and not returned since
 	// the content store cannot be cleanly rolled back.